Unbeknownst to me, the docker image produced by previous versions of guix-builder actually
had a hidden dependency on the hosts /gnu/store. I have not been able to fully characterize
it, but the following proves it to be true.
This fails with an error 139, segfault:
docker run -it guix-builder:latest
However it succeeds when provided the hosts guix store:
docker run -it -v /gnu/store:/gnu/store:ro guix-builder:latest
By using GUIX_EXECUTION_ENGINE=proot (which is implied by the '-RR' option to 'guix pack'),
we avoid the segfaults and hidden dependency on the hosts /gnu/store. Sadly using proot will
have performance impacts, but I'm not sure yet to what extent this will impact my usecase.